It is quicker to do a handful of superfluous compares at the end of
each line than it is to compute and keep track of and compare the
remaining line length the whole time.

The typical line is some sixty characters long, the typical search
string ten characters -- with a shorter search string the speedup is
even higher: some fifteen percent.  Only when the string is longer
than half the average line length does searching become slower with
this new method.

All this for a UTF-8 locale.  For a C locale it makes no difference.